The present invention relates to a grill for fitting into the frame of a sliding window or door to hold the window or door open for admission of fresh air without the risk of insects, animal debris and the like from entering and which is adjustable to fit a range of window frame widths.
Normally, such ventilating grills are of a fixed length and are designed for use in window frames of a specific width. This means that a different window grill has to be produced for each width of window frame.
Alternatively, there is an adjustable sliding type assembly which consists of two rectangular, screened pairs slidably and telescopically engaged with one another and that can be adjusted lengthwise. However, when in place, there is a central area which includes two layers of screen where the two portions overlap and also a pair of vertical frame bars (the inner end bars of each frame portion) which may be close together or spaced apart, depending upon the position of the two portions. Both the double screen section and the frame bars interfere with the visibility through the screen assembly.